In the field of two dimensional sensor arrays it is generally known to connect circuits and sensors by means of bendable and/or stretchable electrical interconnects in order to provide flexible and/or stretchable sensor arrays. Such stretchable and/or bendable circuits and sensors are of growing importance in the field of bio-medical systems since they can be formed or shaped in such a way that they match with the human body such as cylindrical intravascular ultrasound transducer or implant sensor arrays such as retinal implant optical sensors.
In the field of minimal-invasive medical instruments, flexible and stretchable circuits are important to form high performance sensor systems like imaging systems which can be attached to cylindrical or spherical instruments. For stretchable capacitive micromachined ultrasound transducer (CMUT) arrays, the rigid chips are thinned and bent around the instruments, which causes mechanical stress within the transducer arrays. For manufacturing a stretchable CMUT array, the individual transducer elements are usually fabricated on a silicon wafer and attached to a flexible layer or foil and separated from each other by an etching process. The individual sensor devices are usually electrically connected to each other by means of electrical interconnects connected to each of the sensor devices in a separate process step. A corresponding capacitive micromachined ultrasound transducer array for a catheter is e.g. known from WO 2012/066477 A1.
The disadvantage of the known circuit arrays and sensor arrays is that the connection of the electrical interconnects during a post-processing step is complicated so that a technical effort for manufacturing the circuit arrays and/or sensor arrays is increased.
From WO 9832595 a flexible skin is known incorporating microelectromechanical devices, wherein the flexible skin comprises silicon islands encapsulated in a polyimide film, wherein the silicon islands are formed by etching silicon wafers to a desirable thickness by wet etching and pattering from the back side by reactive ion etching.
From US 2006/0255433 A1 a semiconductor-containing flexible skin is known which is suitable for use in intelligent textile applications including a metal layer, an insulating layer and one or more semiconductor islands sandwiched between a first flexible polymer layer and a second flexible polymer layer.
From J. Chen: “Topical Review; Capacitive micromachined ultrasonic transducer arrays for minimally invasive medical ultrasound” in Journal of Micromechanics and Microengineering, Vol. 20, No. 2, 1 Feb. 2010, page 23001 an assembly of a planar monolithic CMUT-array is known, wherein imager plates are connected to each other by flexible dielectric membranes fabricated monolithically with the transducer. From EP 1 883 107 A2 a packaged microelectronic device is known comprising at least one electrode comprising a chip embedded in a package, wherein the chips are connected to each other by flexible electrical interconnects.